Network Rail has warned train passengers who travel between London and Brighton that major closures - including one lasting nine days - will be taking place next year.

As part of plans to upgrade the Brighton Main Line, including work to improve tracks, signals and drainage on the route, stations and sections of the line will be closed on certain days in January and February.

Network Rail says the work will help to improve the reliability of train services on the line, which has been described as one of the least reliable in the south east.

The £67million upgrade includes “extensive” works in three Victorian tunnels to reduce leaking.

Network Rail, along with Gatwick Express, Southern and Thameslink have launched a new travel advice website to give passengers information about the closures so they can plan ahead.

Line closures to allow ‘huge amount of work’

Paul Harwood, Network Rail’s Director of South East Route Investment, said: ""By closing the line for one week in February we will be able carry out a huge amount of work simply not possible in more limited weekend closures, turning the Brighton Main Line from one of the least to most reliable routes on our network.

"I'd encourage passengers to take every opportunity to plan for their journey to make sure they can get to their destinations on time or make alternative arrangements."

Commuters are being warned to plan ahead to factor in the disruption (Image: Kirsty O'Connor/PA Wire)

When will there be closures?

The work will require several line closures to come on January 6, February 9 and 10 and for 9 days from February 16 to 24. There will then be weekend closures on March 2 , 23 and 30, April 6 and a final one day closure on May 5.

Where will be affected by the closures?

No trains will run between Three Bridges and Brighton/Lewes via Haywards Heath. Direct services between London and Brighton will continue to run albeit diverted via Littlehampton and Horsham. A network of replacement bus services will operate for the intermediate stations between Three Bridges and Brighton and between Three Bridges and Lewes for the East Coastway. Passengers should allow considerably more time for their journeys during these periods.

Three Bridges station, Crawley (Image: Grant Melton)

Work to be ‘very disruptive’

Keith Jipps, Govia Thameslink Railway’s Infrastructure Director, said: "We've been pulling out all the stops to make sure passengers have been informed about the closures on the Brighton Main Line so far but now we really need to reach those passengers likely to travel during February half term.

“This work will be very disruptive and journeys will take longer. Passengers should log on to BrightonMainLine.co.uk for the most advanced information on how the closure will affect them and talk to our special closure awareness station staff at the sessions that have been arranged over the next couple of weeks."

Network Rail says work to improve the line has already taken place at 25 separate sites and has included the renewal of 2.7 miles of conductor rail, 532 yards of track and 15 signals together with the replacement of thousands of tonnes of track ballast.

Which tunnels are being fixed?

Balcombe, Clayton, Patcham and Haywards Heath tunnels – and the railway which runs through them. A major programme to stem leaks into the tunnels and provide reliable drainage away from the tracks will take place, while sections of the track, third rail power system and signalling will be replaced or upgraded. Elsewhere, track will be renewed, sets of points, which enable trains to switch between tracks, will be replaced and fencing will be improved to deter trespassers.

Who is paying for the upgrades?

The £67m investment is part of a £300m government-funded programme to boost infrastructure resilience and reliability on the busiest routes in the south east. It is hoped to reduce delays on the line by around 15% when complete.

A full closure list can be found on the Brighton Mainline Upgrade website here: www.brightonmainline.co.uk along with extensive travel advice.

To sign up for free alerts and to find out more about the work – including the dates of planned weekend closures – go to www.brightonmainline.co.uk . News and information will also be shared on Twitter, @brighton_line .